Shelf evaporator



Jan. 6, 1942. I w. E. M CULLOUGI -L 2,268,835

SHELF EVAPORATOR Filed Nov. 17, 1939 2 Sheets-Sheet l xmxxxxmxxx v INVENTOR. E- MV/fam E. M q

ATTORNEYS.

Jan. 6, 1942. w. E. McCULLOUGH 2,268,885

SHELF EVAPORATOR Filed Nov. 17, 1939 2 Sheets-Sheet 2 INVENTOR. MW/om E lfc'C'l/flouy BY Patented Jan. 6, 1942 UNITED STATES PATENT OFFICE SHELF EVAPORATOB I William E. McCullough, DetroihMicln, assiguor to Bohn Aluminum a Brass Corporation, Detroit, Mich., a corporation of Michigan Application November 17, 1939, Serial No. 304,997

. v '1 Claims.

This invention reiates tothe heat exchange art,'and particularly to the art of refrigeration.

It has previously been proposed, as in Summers U. S. Patent No. 2,132,836, to cool a refrigerator by an evaporator in the form of a fiat element which can be used as a shelf, thus making available for food storage the space that is conventerminate in dovetailed flanges IS. The tube l4 tionally taken up by the box type of evaporator.

The present invention improves upon the structure shown in the Summers patent by providing a foraminous evaporator shelf through which air may circulate freely, so that food may rest directly on the cooled shelf while the circulation of air equalizes the temperature throughout the compartment in which the shelf is located.

Another feature of the present invention resides in.the provision of shelves with varying spacing of the tubing which carries the refrigerating fluid. In some of the shelves the runs of tubing may be placed close together thus incorporating a relatively great length of the cooling tubing for use where very low temperatures are to be maintained, while in other shelves the runs of tubing may be placed farther apart for use where higher temperatures are desired.

In carrying out this invention each shelf is preferably built up from a single strip of stock having a tube and fins, the fins being foraminous and being expanded to the desired width.

These and other objects and advantages of the invention will become apparent as the description proceeds. v

While preferred forms of the invention are disclosed herein for purposes of illustration, various changes may be made in the structure without departing from the spirit of the invention as herein set forth and claimed.

In the drawings:

Fig. 1 is a vertical section through a refrigerator embodying the invention.

Fig. 2 is a plan view partly in section showing one of the shelf evaporators.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a perspective of a; piece of the strip material as originally formed.

Fig. 5 is a perspective of a piece of the strip material after it has been expanded.

Fig. 6 is a vertical section showing another arrangement for utilizing the invention in a refrigerator.

The improved shelf evaporator of this invention is shown in Fig. 1 installed in a refrigerator of the domestic type which comprises a cabinet l0 having a door ll.

l2 and I3 are shelf evapoand flanges l6 project from one face of the strip, leaving the other face fiat. At present I prefer to extrude this stock from aluminum, but

it can of course be made by other processes and of other materials suitable for the purpose. The use of a strip of this conformation to construct evaporator units is disclosed in U. S. patent to Higham et al., No. 2,162,083. Prior tothe fabrication of this strip into shelf evaporators, the fins are cut with a plurality of slots extending parallel to the tube I4 and arranged in staggered relation to each other, and the two dovetailed flanges iii are then gripped and pulled apart,v

thus expanding the fins I5 in a manner well understood in the expanded sheet metal art. The expanded strip has its fins pierced by a plurality of diamond-shaped openings as shown in Fig. 5.

After the fins I5 have been thus expanded to the desired extent, parts of these fins on opposite sides of the tube M are removed at each end portion ll of the strip, and at intermediate portions l8. The intermediate portions l8 are then bent so as to bring the second run of the strip into a position with one of its dovetailed flanges l6 adjacent a dovetailed flange l6 offthe first run. Each of the intermediate portions I8 is similarly bent, afterwhich the juxtaposed dovetailed flanges are fastened to each other in any suitable manner, as by pinching over them clip strips l9 according to the teachings of Higham Patent 2,162,083. The strip of material is now in the condition illustrated in Figs. '2 and 3, being in the form of a continuous sheet with a fiat surface on the upper side and with the-tubes I4 and flanges i6 projecting downwardly from the under side. The tube ll winds sinuously across the underside of the sheet but forms a continuous conduit free from joints.

The shelf evaporator thus formed may be mounted in a refrigerator in any preferred manner. One advantageous method of mounting the shelf is shown in Figs. 1 and 2 in which the shelf is placed with the runs of tubing ll extending parallel to the back wall of the refrigerator cabinet. With this arrangement it is possible to support the shelf by securing angle brackets 20 to the side walls of the cabinet in a position to engage under the bent portions l8 and end portions [1 of the tube I4. With this arrangement the tube I 4 and dovetail flanges l6 form ribbing to stiffen the shelf on the dimension of its greatest length.

The end portions ll may be connected in any suitable manner to any preferred type of refrigeration system. In the form illustrated the ends IT project into the insulated walls of the cabinet where they are connected to the leads of a refrigeration system.

An important advantage of the evaporator shelf of this invention lies in the fact that its foraminous construction permits air to circulate relatively freely through the shelf so that the shelf not only provides efiicient cooling contact with objects placed on the shelf, but also provides for the maintenance of a fairly uniform refrigerating temperature throughout the compartment in which the shelf is located.

A refrigerator may be constructed with only a single evaporator shelf, although a plurality of such shelves may be used as indicated at [2 and I3 in Fig. 1. 2| is a conventional wire shelf. The shelf l3 of Fig. 1 has its fins l5 expanded laterally farther than those of shelf l2, and hence there are fewer runs of the tube M on the underside of shelf l3. As the result the shelf I3 is not provided with as much refrigeration capacity as shelf l2, and hence can be kept at a higher refrigerating temperature. By thus varying the degree of expansion of the fins on different shelves, it is possible to provide refrigeration zones for different purposes, such as for freezing ice cubes, etc.

In some cases it may be desired to provide a refrigerator with separate compartments in which the temperatures are maintained within different ranges. -A construction of this kind is illustrated in Fig. 6 in which compartments 22, 23 and 24 are separated from each other by insulated partitions 25. A shelf evaporator constructed according to this invention is located in each of these compartments. The shelf evaporators in these different compartments can be constructed with varying degrees of expansion as just explained to place a different amount of refrigerating tubing in the difierent compartments. Thus, as shown in Fig. 6, the shelf evaporator-26 is provided with four runs of tubing ll, the evaporator 21 is provided with five rims, and the evaporator 28 is provided with six runs of the tubing.

Details of the refrigeration system do not form a part of the present invention, and it will be obvious to those skilled in the art that the shelf evaporators can be connected to any preferred control mechanism, such as expansion valves,

multiple control valves, etc., to provide suitable being foraminous to permit circulation of air through the shelf. x

2. In an evaporator shelf for refrigerators the improvement which comprises; a shelf formed from a single strip of material having fins homogeneous with a tube, the flns being foraminous to permit circulation of air through the shelf.

3. In an evaporator shelf for refrigerators the improvement which comprises; a shelf formed from a plurality of runs of strip stock, the strip stock including a tube portion and lateral fins homogeneous with the tube portion, the fins being pierced by a plurality of diamond-shaped openings.

4. In an evaporator shelf for refrigerators the improvement which comprises; a shelf formed from a plurality of runs of strip stock, the strip stock including a tube portion and lateral fins homogeneous with the tube portion, the lateral fins ending in side flanges by which adjacent runs are secured together, the flns being pierced by a plurality of diamond-shaped openings.

5. The improvement specified in claim 4 in which the tubes and flanges project from one face of the stock, leaving the other face flat.

6. In a refrigerator of the type in which the temperatures of a plurality of separate compartments are maintained within different ranges by shelf evaporators individual to the compartments, the iprovement which comprises; a foraminous evaporator shelf provided with cooling tubes in each compartment between the top and bottom thereof, the tubes on the evaporator shelf in one compartment being more numerous and closer together than the tubes on the evaporator shelf in another compartment.

7. In a refrigerator of the type having a plurality of evaporator shelves, the improvement which comprises shelves having cooling tubing with foraminous fins homogeneous with the tubing, one shelf having runs of cooling tubing spaced closer together and a greater length of cooling tubing than has another shelf.

WILLIAM E. MCCULLOUGH. 

